WASHINGTON — The co-founder of Plaxo, a contact management and social networking startup,  has been charged with murdering his ex-wife’s new husband, in Ashburn, Virginia.

According to the Loudoun County Sheriff’s Office, 38-year-old Minh Nguyen entered the Ashburn Village townhome of his ex-wife on January 15 and shot Corey Mattison, who had recently married Nguyen’s ex-wife.

Mattison’s wife was not home when he was killed, but two children were home. His wife returned to the townhome in the 44200 block of Sonora Lane with another child, as the incident was unfolding.

The co-founder of Plaxo was Napster pioneer Sean Parker.

On its website, Plaxo  calls itself the world’s leading online address box, storing over 50 million address books with 3.7 billion contacts.

Plaxo was acquired by Comcast Interactive in June 2008.

Nguyen’s LinkedIn profile lists him as a venture advisor with TandemNSI, which links entrepreneurs with government agencies. A spokesman tells WTOP Nguyen consulted approximately 5 hours per week until November.

Other startups listed on Nguyen’s LinkedIn profile include App Press LLC and Syllabuster.

Between 1994 and 1996 Nguyen was a technical producer/interface programmer at AOL, according to his LinkedIn page.

Nguyen is charged with first-degree murder and use of a firearm during the commission of a felony. He remains held at the Loudoun County Adult Detention Center on no bond.

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